Design and Experimental Study of a Probe for Crankshaft Full-automatic Measuring Machine

Abstract The Crankshaft Full-automatic Measuring Machine (CFMM) features high accuracy, high efficiency and complete measurement parameters, and represents the forefront of a geometric crankshaft accuracy measuring instrument. One of its core technologies is the high-precision radial following the crankshaft connecting rod journal measurement. In this paper, an independent probe design scheme combining the flexible dual-complex parallel four-bar guide mechanism and double displacement sensors based on the contact measurement method was proposed. It was suitable for the measurement of precision parts with eccentric characteristics such as crankshaft and camshaft measurement. Taking the spring as the flexible part, the probe prototype’s optimization design, processing and assembly were completed, the test device was built, and the system accuracy was calibrated under various positions and feed quantities of the probe. The results revealed that the expanded measurement uncertainty after double-sensor compensation was enhanced from 1.53 μm in single-sensor measurement to 0.44 μm, satisfying the high-precision requirements of engineering measurement accuracy and reducing the measurement cost.